Anti-fatigue elastic fabric

ABSTRACT

An elastic fabric with anti-fatigue property, with three types of constituent yarns, in which the first type of yarns is made of chemical filaments, the second type of yarns and third type of yarns are elastic yarns made of the same or different materials, but preferably having different fiber densities, and the first type of yarns and second type of yarns form a number of locking nodes via inter-looping of the yarns and the second type of yarns and third type of yarns form a number of locking points by melting of the yarns during a heat treating process.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Chinese Patent Application No. 201210266021.9, filed Jul. 27, 2012, the contents of which are hereby incorporated by reference.

FIELD OF THE INVENTION

This invention relates to the textile and garment industry. More particular, it relates to a warp knitted elastic fabric that can withstand external forces exerted by stretching and washing actions and maintain flatness and smoothness and thus has a wide range of applications in production of underwear and sportswear. It also relates to a method for making such fabric, which relies on forming special elastic yarn loops and cross-linking them under heat treatment so as to prevent loop movement when under the influence of external forces.

BACKGROUND OF THE INVENTION

At present, warp knitted elastic fabric is widely applied to ladies' underwear, corset, etc, as they generally attach great importance to shaping and maintaining a good profile of the body. Thus the potential of ladies' underwear market of adjustable underwear, corsets, etc. is large, and the same of the sportswear market. To meet the need of the market, it is crucial for the fabric material to have good external appearance and high elasticity ever after subject to adverse effects exerted by external forces.

At present, the existing elastic fabric widely used in underwear and corset is the type known as “satin net”. This fabric is fabricated with common Raschel warp knitting machines, composed of nylon filament yarn and spandex yarn, and usually fabricated with two guide bars. It is of a structure with variable pillar stitch and three-stitch variable weft insertion. During the knitting process on the warp knitting machine, the yarns move forward and backwards periodically on the yarn guide bars, and the knitting needles move up and down periodically on the needle bed. Different fabrics can be made by changing proportions of the yarns and parameters of the moving components. These types of fabrics have excellent aesthetic appearance. This prior art technology is shown in FIG. 1.

However, the fabrics made in accordance with the aforesaid method have an inevitable defect in terms of elastic performance. It was found that it cannot resist external forces such as multiple stretches and repeated washings, often leading to serious quality problems due to the failure in resisting the fabric fatigue.

For example, spandex yarns may move out of place in the fabric and form bulges or unevenness, and some yarns may even break when the fabric goes through tensile fatigue test (7500 times of stretches). Yarns dislocation (relative to each other) happens during the washing test (25 times of machine washing) due to mechanical friction and tension caused by water and detergent. These defects affect the appearance and service time of the garments. The quality problems induced by repeated stretches and washings are brought about by the same underlying fact: relative movement of the filament yarns with respect to elastic spandex yarns under the external forces, which causes the fabric to lose the original shape and results in severe damage of the cloth.

SUMMARY OF THE INVENTION

Therefore, the main object of the present invention is to design a type of elastic fabric with a super anti-fatigue ability and being able to resist the external forces brought by multiple stretches and washings.

To realize the above technical purpose of this invention, the present invention provides a solution that is to design a special loop pattern of yarns and then subject it to a heat treatment process to result in a type of super anti-fatigue elastic fabric with higher resistance to mechanical tensile and washing fatigue.

Another object of this invention is to obtain a type of super anti-fatigue elastic fabric provided with a various degree of glossiness and different external visual effects.

A further object of this invention is to obtain a type of super anti-fatigue elastic fabric with a unit area of 100 g/m²-260 g/m² and various thicknesses to broaden the range of application in the garment industry.

Another object of this invention is to obtain a type of super anti-fatigue warp knitting satin net.

According to the technical purposes of the present invention, a type of super anti-fatigue fabric is produced on Raschel warp knitting machine by adopting a special loop pattern (an example is shown in FIG. 2 b) and a proper heat treatment process.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows the stitch pattern of the prior art technology.

FIG. 2 shows the stitch pattern of the fabric of the present invention: (a) loop pattern of nylon fiber yarns 1 on the first guide bar; (b) loop pattern of spandex yarn 2 on the second guide bar; and (c) loop pattern of spandex yarn 3 on the third guide bar.

FIG. 3 shows the knitting needle on the RSE machine used in the particular embodiment.

FIG. 4 shows the groove needle on the same RSE machine as above.

FIG. 5 shows the yarn guide needle on the same RSE machine as above.

FIG. 6 shows the sinker on the same RSE machine as above.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be made to the drawings and the following description in which there are illustrated and described preferred embodiments of the invention.

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS OF THE INVENTION Warping of Yarns

1) Warping of fully-drawn nylon yarns

The warping machine used is Karl·Mayer DS 21/30 NC-2, passive yarn feeding.

Environment temperature for warping is 23° C.

Environmental humidity for warping is 65%.

Set the tension for the machine under the proper temperature and humidity conditions to ensure the balanced tension of the warping yarn sheet necessary for a smooth process of knitting.

2) Warping of elastic spandex yarns.

The warping machine used is Karl·Mayer DSE-H21/30 NC-2, positive yarn feeding.

Environment temperature for warping is 24° C.

Environmental humidity for warping is 78%.

Set the tension for the machine and the drafting parameters (spandex yarns with different thicknesses have different drafting values) under the proper temperature and humidity conditions.

Knitting Process

The knitting machine used is Karl·MayerRSE 4-1.

The threading method is full-set threading.

The specific loop formation on Karl·Mayer RSE machine is accompanied by combined actions of the needle body (or shaft), core (or tongue), yarn guide needle, and sinker of the groove needle. Specific steps of the looping process are as follows:

Sloughing off: the groove needle and its core are at the lowest position, the yarn guide needle is at the forefront position and carries out underlapping, and the sinker moves forward to the pulling direction (i.e. the loop holding position) of the machine.

Drawing-off loop: the sinker moves to the forefront of the machine. The groove needle begins to rise, the core needle is still at the lowest position, and the yarn guide bar terminates the movement of shog.

The yarn guide needle swinging backwards: The groove needle continues to rise and the core begins to ascend, but the top of the core remains in the groove, the underlapping is already over, and the sinker still holds the old loop. At this moment, the sinker goes a little bit backwards to loosen the held loop. The yarn guide needle moves toward the front of the needle, and is ready for over lapping.

Over lapping: Over lapping is carried out after the yarn guide needle reaches the back of the machine, the sinker loosens the held loop, and the core continues to rise after it passes through the old loop.

The yarn being placed into the needle hook: The yarn guide needle swings to the front of the machine, the groove needle descends, and the yarn is placed into the needle hook. The core gradually moves out of the groove and, at this moment, the old loop is tensioned again.

Closing the needle hook: The sinker moves to the back of the machine, the groove needle and the core descend, and the core closes the needle hook. The old loop slides up along the core from the needle bar. The yarn guide needle is in front of the machine and ready for underlapping.

Sloughing off: the groove needle and the core descend below the sinker simultaneously to start “sloughing off”. Meanwhile the needle hook draws the yarns to form a new loop. The sinker moves to the front of the machine, and the yarn guide needle starts underlapping.

The fabric is produced through consorted movements of all the moving parts on the machine according to the loop forming method and the predetermined stitch pattern. In the fabric thus produced, there are open-ended loops, close-ended loops, and weft insertion yarns for the continuous stitches.

The fabric of the present invention is made of two types of yarns with three different densities: chemical fiber filament 1, elastic yarn 2, and elastic yarn 3.

Chemical fiber filament 1 is made of the known material, e.g. polyester fiber or polyamide fiber. Polyamide fibers are usually polyamide 6 and polyamide 66. The fiber density is about 20-70 deniers. The fiber density is expressed as deniers of chemical fiber filaments, i.e. the total weight (grams) of the 9000-meter fiber.

Elastic fibers 2 and 3 are made of the known elastic material, especially elastomeric polymers, e.g. the polyurethane elastic fiber. The proper fiber density for 2 is about 10-70 deniers and the proper fiber number for 3 is about 70-420 deniers.

Yarns 1, 2, and 3 are arranged on the above exemplified type of warp knitting machine for making the fabric of the present invention. For this particular embodiment, the stitch patterns for yarns 1, 2, and 3 are shown in FIGS. 2 a, 2 b and 2 c, respectively.

Yarn 1 is arranged on the first yarn guide bar. Structure loops of yarn 1 are formed cooperatively via the vertical movement of the knitting needle and the horizontal movement of the yarn guide needle.

Similarly, elastic yarns 2 and 3 are respectively arranged on the second and the third guide bars. The order of elastic yarns 2 and 3 are not strictly important. The anti-fatigue elastic fabric is produced from three types of yarns via the requisite reciprocating motions of yarn guide needle and in accordance to the predetermined texture structure.

In general, a person of ordinary skill in the art, once given the stitch pattern (such as shown in FIG. 2), would be able to set up the machine to produce the fabric as intended. Similarly, once given the purpose of the invention and the method of realizing the purpose via the examples disclosed herewith, a person of ordinary skill in the art would be able to select other alternative yarns as yarn 1, 2, and 3, respectively, to achieve the same goal of the present invention.

FIG. 2 is an exemplary yarn laying digital diagram (stitch diagram) of the fabric according to the present invention. As shown, all three types of yarns adopt a six-row periodic repeating loop pattern.

FIG. 2 also shows rows of dots, each of which represents a knitting needle at its temporary location in the moment. A row of the dots represents a plurality of different knitting needles, positioned according to each needle's horizontal position order. A column of dots represents periodic positions of a single knitting needle, determined by periodic movement of yarns and the knitting needle. The blank space between rows represents the positions of the yarn carried by the yarn guide needle. In particular, the yarn guide needle carries the warp yarn to circle the knitting needle and forms closed-ended loops or open-ended loops.

The six-row loops pattern formed by yarns 1, 2, and 3 as shown in FIG. 2 is a basis to realize the goal of the present invention. The knitting process always starts from the same knitting needle but in different knitting directions. Three-stitch interval knitting pattern of yarn 1 is applied to two adjacent knitting needles. This is known as the variable pillar stitch. The single needle variable pillar stitch is applied to Yarn 2. It plays a key role in the fabric despite its simple structure. Yarn 3 does not form loops, and is just for yarn laying on the adjacent three knitting stitches, i.e. the so-called three-stitch weft insertion structure. The structure of the fabric according to the present invention is defined by the movement of the three groups of yarn guide needles, wherein the front and the rear settings lead to the overlapping relations of yarns on the vertical direction and result in different characteristics of the front and back surfaces of the fabric: the front of the fabric is smooth and shiny and the longitudinal veins are evident. However, the back surface of the fabric is darker and dull and the transverse circular veins are more evident.

It is understood that the fabric produced according to the aforementioned method can be made on different types of Raschel machines, as alone as an elastic yarn with proper thermoplastic property is provided so that at a specific temperature (180° C-200° C.) in the process of heat treatment it adhere to each other and/or to other yarns to prevent sliding of loops. In this way, the resulting elastic fabric will have super anti-fatigue properties.

The elastic fabric of this invention is made of chemical filament yarn 1, elastic yarn 2 (for example, spandex yarn), and elastic yarn 3 (for example, spandex yarn) arranged respectively on different yarn guide bars to form the fabric according to predetermined structures of loops so that yarn 1 and elastic spandex yarn 2 form loops and lock each other at a specific point, forming a stable node between yarn 1 and yarn 2. In subsequent heat treatment, yarn 2 and yarn 3, both being melt to some degree, will form a stable adhesive connection. In other words, a stable fabric structure is formed between yarn 1 and yarn 3 mediated by yarn 2 because it is locked with both yarn 1 and yarn 3. The elastic fabric thus produced has a super anti-fatigue property. The heat treatment can be accomplished by simply subjecting the dry fabric to a temperature between 180° C.-220° C. for 1-2 minutes, a very simple step.

Of course, the invention is not limited by the numbers of needles on the knitting machine or the yarn thickness as shown in the specific embodiment here. For example, it can be used to produce a wide weight range of fabrics, such as 100 g/m2-260 g/m2, and a wide range of fabric strength to meet different requirements of the garment industry.

Thanks to the interlocking loop structures between the yarns of the fabric, the fabric of the present invention has the following additional advantageous effects:

It has better visual effects, showing a flat and smooth surface appearance.

It has smaller meshes and a better air permeability regardless of the thickness of the fabric.

The fabric of the invention has a less tendency of curling.

Testing: Take a 9 cm width strip of the fabric made according to the above disclosed embodiment, either wet or dry, and stretch it with a force of 1.5 kg and repeat for 7500 times. After the test, the surface of the fabric remained flat and smooth, demonstrating that it is an ideal fabric with a super anti-fatigue property.

While there have been described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes, in the form and details of the embodiments illustrated, may be made by those skilled in the art without departing from the spirit of the invention. The invention is not limited by the embodiments described above which are presented as examples only but can be modified in various ways within the scope of protection defined by the appended patent claims. 

1. An elastic fabric with anti-fatigue property, comprising a first type of yarns, a second type of yarns, and a third type of yarns; said first type of yarns being made of chemical filaments, and said second type of yarns and said third type of yams being elastic yarns made of the same or different materials; and further comprising a plurality of locking nodes formed from said first type of yarns and second type of yams and a plurality of locking points between said second type of yarns and said third type of yarns.
 2. The elastic fabric of claim 1, wherein said yarns of first type are made of polyester or polyamide, and said yarns of second type and third type are made of spandex.
 3. The elastic fabric of claim 2, wherein said yarns of second type and third type are of different fiber densities.
 4. The elastic fabric of claim 3, wherein said yarns of second type are 10-70 deniers and said yarns of third type are 70-420 denier.
 5. The elastic fabric of claim 4, wherein said plurality of locking points are formed during a heat treating process at a temperature between 180° C. and 220° C.
 6. The elastic fabric of claim 5, wherein said heat treating process lasts 1 to 2 minutes.
 7. The elastic fabric of claim 1, wherein said yarns of first type adopts a six-row variable pillar stitch, in which an open-ended loop and a closed-ended loop combine with each other alternatively.
 8. The elastic fabric of claim 7, wherein said yarns of second type adopts a single variable pillar stitch, in which open-ended loops and weft insertion structures combine with each other alternatively.
 9. The elastic fabric of claim 8, wherein said yarns of third type adopts a three-stitch Weft insertion structure, in which the yarns are not looping in the fabric. 